Discovery of X‐Ray Jets in the Microquasar H1743−322

We report on the formation and evolution of two large-scale,synchrotron-emitting jets from the black hole candidate H 1743-322 followingits reactivation in 2003. In November 2003 after the end of its 2003 outburst,we noticed, in observations with the Australia Telescope Compact Array, thepresence of a new and variable radio source about 4.6" to the East of H1743-322, that was later found to move away from H 1743-322. In February 2004,we detected a radio source to the West of H 1743-322, symmetrically placedrelative to the Eastern jet. In 2004, follow-up X-ray observations with {\emChandra} led to the discovery of X-ray emission associated with the two radiosources. This likely indicates that we are witnessing the interaction ofrelativistic jets from H 1743-322 with the interstellar medium causing in-situparticle acceleration. The spectral energy distribution of the jets during thedecay phase is consistent with a classical synchrotron spectrum of a singleelectron distribution from radio up to X-rays, implying the production of veryhigh energy ($>$ 10 TeV) particles in those jets. We discuss the jetkinematics, highlighting the presence of a significantly relativistic flow in H1743-322 almost a year after the ejection event.Comment: Accepted for publication in The Astrophysical Journal. 17 pages, 9 figure